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Wednesday, 14 January 2015

Hydrogen

hyderogen

Hydrogen occupies the first place in the periodic classification of Mendeleev. Hydrogen is an atom consists of a single proton around which revolves a single electron. Its atomic weight is 1, 00797.

Physical Properties

Hydrogen is an odorless, colorless gas. It is the lightest of all the substances. its density in air is 0.07.

The hydrogen is after the helium gas more difficult to liquefy. Its critical temperature of 240 ºC, its boiling point at atmospheric pressure is 252.7 ºC, solidifies at 259.2 ºC. It is a fair conductor of heat and electricity.

The hydrogen molecule is diatomic, at room temperature these molecules are stable isomers, called ortho hydrogen and Para hydrogen.

Chemical Properties

2 molecule of methane

Generally active little cold, hydrogen gives rise, in hot or in the presence of catalysts, in numerous reactions. Has oxidation number 1, so it is mono valiant. It combines directly to most non-metals and alkali metals and alkaline earth metals. The speed of the reaction and decrease the amount of heat carried by fluorine to iodine

The combination with the oxygen to give water is often the case with explosion at elevated temperature or in the presence of a catalyst (platinum sponge). Combines with sulfur to 250 ºC; the reaction with nitrogen, which gives rise to ammonia, requires the use of catalysts, high temperatures and high pressures. Reacts with the carbon to 1,100 ° C to generate methane; when operating electric arc is obtained instead acetylene